1. Field of the Invention
This invention relates to a textile product having flame retardant properties provided by intumescent particles coated on the upper surface of a tufting primary backing that provide enhanced flame and/or smoke retardant properties to the textile product. The invention also relates to methods of manufacturing such a textile product.
2. Description of the Related Art
Many commercial textile products are required by law to have smoke suppressant and flame retardant properties in order to help prevent smoke generation and flame spread through the textile products in the event of a fire. Typically, most carpet structures have nylon fibers bonded, tufted, or otherwise joined to a primary backing layer, collectively referred to as a face cloth. The face cloth is then bonded to a back coating layer, commonly made of polyvinylchloride (PVC) or PVC resin, which is quite flammable. Although nylon fibers do not support flames or combustion well, heat from a fire can heat or melt the nylon fibers, which in turn can ignite the PVC, providing a sustained flame source and causing the nylon fibers to burn and emit noxious gases.
Thus, in order to meet the flame and smoke standards, it is fairly common for textile products to be comprised of fibers having flame retardant or smoke suppressant properties. See generally U.S. Pat. No. 4,012,546 to Schwartz et al., which discloses a carpet containing flame retardant fibers, the disclosure of which is hereby incorporated by reference. Alternatively, many textile products consist of at least two distinct components where a textile material is used in conjunction with various additional backing layers or blocking sheets that impart smoke suppressant and flame retardant properties to a given textile product. For instance, much transportation upholstery material is used in conjunction with separate fire blocking sheet layers.
As a further example, many carpets include secondary or tertiary backing layers that have smoke suppressant and flame retardant properties. For instance, some carpets incorporate polybrominated biphenyl oxides, such as decabromobiphenyl oxide (“decabrome”), or antimony oxide in these additional backing layers. However, decabrome is very expensive and antimony oxide may pose toxicity problems. The practice of including fire block sheets and separate backing layers to increase smoke suppression and flame retardancy is expensive and is often difficult to incorporate in the manufacturing process of textile products.
Another attempt to provide textile products with flame retardant and smoke suppressant properties is described by U.S. Pat. No. 4,824,709, to Tschirch, the disclosure of which is hereby incorporated by reference. This patent describes incorporating intumescent particles into a backcoating of a textile product. This practice, however, does not prevent the flame from reaching the backcoating layer, but is merely an attempt to attenuate the effects of a flame once it does reach the backcoating layer. One reason this approach may be considered acceptable is that nylon fibers are not particularly flammable, as noted above.
However, advanced technology has led to the manufacture of carpet fibers from materials other than nylon. In some instances, the new carpet fiber materials provide enhanced properties over nylon fibers, such as increased softness, durability, and so forth. On the other hand, the fibers are often not as flame resistant as nylon fibers. This presents additional difficulties for manufacturers of such products.
The invention of U.S. Pat. No. 4,824,709, to Tschirch would not be effective for use with carpets that have fibers made from a flammable material. Specifically, nylon fibers do not propagate a flame, and as such, there has not been as much need to provide a flame resistant material in close proximity to the fibers. On the other hand, carpets having fibers made of materials that are more flammable than nylon present an increased challenge to providing a flame retarding mechanism. Due to regulations and also due to manufacturers' incentives to provide flame resistant textile products, additional products and methods must be explored for use with less flame resistant carpet fibers. Additionally, it would also be beneficial to provide a carpet product that prevents a flame from ever reaching the flammable backcoating of the carpet.
U.S. Pat. No. 3,859,151 to Vincent, the disclosure of which is incorporated by reference, discusses providing a carpet with a primary backing support for tufted yarn that bears microcapsules containing volatile or volatilizable flame-retarding agent. The agent may also be incorporated into an adhesive applied to the back of the primary backing. In use, the flame-retarding agent is released from the microcapsules under the action of heat to volatize and form a flame-resistant, gaseous atmosphere surrounding each of the yarn tufts. The reference suggests that the use of unencapsulated flame-retardants is not as useful because the volatile, toxic material would evaporate from the adhesive and not be available for protection of the carpet. Microcapsules may contain a gas that expands when heated and escapes to yield free gas, and therefore flame retardance.